The present invention relates to an underseal composition for motor vehicles.
Metal-coating agents or metal-coating compositions based on polyvinyl chloride, plasticizers, pigments and/or fillers, such as chalk, have already been disclosed (cf., inter alia, German Auslegeschrift 1,229,220). It has furthermore been disclosed that the processability in certain areas of application, for example the coating of metals, is accompanied by difficulties, inasmuch as requirements such as adhesive strength, in addition to good processability, must be satisfied.
Even greater demands are made on underseal compositions for motor vehicles, for example based on polyvinyl chloride, since the underseal compositions must not only be easy to apply, have good adhesion and the like, but must also have a certain resistance to chipping and other mechanical influences. It has therefore been shown that numerous plastisols, which can be employed, for example, for the coating of paper, for the production of wallpaper, for the production of floor coverings, for sheathing cables and so on, are not suitable as underseal agents or compositions.
Commonly assigned German Patent Application P 38 01 649.4, corresponding to U.S. application Ser. No. 07/299,338, discloses an underseal composition for motor vehicles, based on polyvinyl chloride, which comprises a filler comprising calcium carbonate particles, with at least a part of the filler being provided with a surface coating comprising a surface treatment agent which comprises at least one saturated or unsaturated carboxylic acid, fatty acid or substituted fatty acid having from 2 to 32 carbon atoms and containing at least one polar group in addition to at least one --COOH group, or a salt of said carboxylic acid or fatty acid. The composition displays improved rheological properties.